instanceof operator works wrong for own components.

import QtQuick 2.15
import QtQuick.Controls 2.15
import QtQuick.Templates 2.15 as T

T.ToolButton {
    id: root

    text: "Foo"
    checkable: true
    implicitWidth: 150
    implicitHeight: 50
    background: Rectangle 
    {
        color: root.down ? "red" : "green"
    }
    contentItem: Label {
        text: "%1".arg(root.text)
        horizontalAlignment: Qt.AlignHCenter
        verticalAlignment: Qt.AlignVCenter
    }
}

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.15

import MyControls 1.0

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    ToolButton {
        id: fooButton

        anchors.centerIn: parent

        width: 150
        height: 50
        visible: true
    }
    Label {
        anchors.top: fooButton.bottom
        width: 300
        height: 50
        text: "fooButton instanceof ToolButton => %1".arg(fooButton instanceof ToolButton)
        background: Rectangle {
            color: "yellow"
        }
    }
}